Antioxidant activity assay based on laccase-generated radicals

Endry Nugroho Prasetyo, Tukayi Kudanga, Walter Steiner, Michael Murkovic, Gibson S. Nyanhongo, Georg M. Guebitz

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

A novel antioxidant activity assay was developed using laccase-oxidized phenolics. In a three-step approach, phenolic compounds were first oxidized by laccase. Laccase was then inhibited using 80% (v/v) methanol which also stabilized the oxidized phenolics which were then used to measure antioxidant activities of ascorbic acid and Trolox. From a number of laccase-oxidized phenolics screened for potential use in the measurement of antioxidant activities, syringaldazine emerged the best, giving results comparable to the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, which is currently used in conventional methods. Like DPPH radicals, two moles of stoichiometric oxidized syringaldazine were reduced by one mole of either ascorbic acid or Trolox. For the first time we show that antioxidant activity can be correlated to oxygen consumption by laccase. Reduction of one molecule of oxygen corresponded to oxidation of four molecules of syringaldazine which in turn is reduced by two molecules of Trolox or ascorbic acid. This study therefore demonstrates the great potential of using laccase-oxidized syringaldazine for the measurement of antioxidant activity.

Original languageEnglish
Pages (from-to)679-687
Number of pages9
JournalAnalytical and Bioanalytical Chemistry
Volume393
Issue number2
DOIs
Publication statusPublished - Jan 2009
Externally publishedYes

Keywords

  • Antioxidant assay
  • Laccase-oxidized phenolics
  • Syringaldazine

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